Automobile body dent repair tool

ABSTRACT

A set of tools for the process generally known as “paintless dent repair” for removing a class of dents in automobile body panels is modified to have interchangeable handles with a range of positions relative to the working end of the tool. Thus, permitting the modified set of tools to be comprised of many fewer individual tools than is the current practice in the art.

RELATED APPLICATIONS

None

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to an improved tool for repairing dents inautomobile body panels by working the back of the dent in the processgenerally known as “paintless dent repair”.

2. Description of the Prior Art

Removing dents in automobile panels historically has been a crudeapplication of hammer blows using various shaped anvils and intermediaryimpact-transfer shapes known as “spoons” and/or drilling through thedent and attaching a puller or slide hammer. Failing to achieve completesuccess with these techniques, the dent was finished by filling withlead or epoxy-like plastics. The resulting work left a damaged orunpainted surface required repainting of the panel and all the attendantproblems of matching colors, surface characteristics, etc., followedover time, by differential fading and weathering.

More recently, especially with the use of the thinner materials inautomobile body panel construction, a process of gently tapping andpushing from the back side has been developed. Because the straighteningprocess itself does not damage the exterior surface, it is generallyknown as “paintless dent repair”

Paintless dent repair is a highly skilled art and requires a largevariety of tool tips at the working end of the tool. In addition to avariety of tips, a variety of end curves, shaft lengths, and shaftdiameters and/or shapes are needed. In most cases the dent is coaxed outwithout disassembly of the auto body, thus, the tools are generally longand thin to reach the dent through whatever openings are available orcan be made without noticeable damage. The long slim design of most ofthe tools predicates the use of very high quality tempered steel. Whichis not only costly, the tools cannot be bent to suit the immediate task.Because a dent can occur in so many diverse locations, the artisanrequires a large set of tools, some differing only by the orientation ofthe handle relative to the working tip.

The space within a door panel, a common place where suitably dentingoften occurs, is especially crowded with window glass, window raisingmechanisms, locks, motors, structural bracing, etc., and the crowding isgetting worse as more gadgetry and structural integrity (for crashprotection) is added with each successive model of automobiles.

Furthermore, occasionally dents to be repaired may be better repairedwith tools not in the conventional set. The present invention moreeasily accommodates the construction of special tools.

Most of the tools in the sets available to the trade have handles formedby bending the shank stock into loops or other shapes for handling. Suchhandles are light weight and somewhat flexible, conditions not alwaysoptimum for the work to be performed. Furthermore, a formed handleusually requires 20 inches of steel rod. This may be 30 to 40% of thesteel used in a typical set of 300 tools. It is apparent that usingshank stock for handles is an inefficient use of the high quality steelrequired in the rest of the tool.

Paintless dent repair tools were first used in Germany by theDaimler-Benz company. Two current suppliers of the tools in the UnitedStates are U.S. Denttools, of Olathe, Kans. and Dentcraft Tools ofOklahoma City, Okla.

In recognition of some of the limitations of the conventional tool set,Mike Cmelik has been awarded U.S. Pat. No. 6,543,270. Mr. Cmelikdiscloses a tool with interchangeable tips and a means for formingcustom temporary end shapes. The movable joint system and need for a tipcoupler makes Mr. Cmelik's tool necessarily thicker than the standard“fencing foil” design. Further, Mr. Cmelik did not anticipate thedesirability of having a variety of handle shapes and/or orientation.

The present invention utilizes a set of separate handle assembliesdesigned specifically for gripping and applying pushing, pulling andtwisting forces. Each handle has a disconnectable joining means betweenthe handle and tool shank. The joining coupling has a square shank sothat the handle may be rotated to any of 4 positions about the axis ofthe tool shank. A workman can assemble a large number of customizedtools from a significantly smaller number of interchangeable components.Thereby significantly reducing the number of individual tool partsrequired to be a complete working set.

Fenders and fender repair have some unique characteristics. A specialfender tool is desirable.

Prior art methods for fender repair comprise the steps of elevating theautomobile, removing the tire and wheel, and perhaps the brake drum,then to use various jacks, hammers, pry bars and other crude methods ofapplying force to straighten out the crumpled fender. Then the fendersurface has to be finished smoothly and repainted. Finally, the wheelhas to be reinstalled. The method using the tool described herein is amuch simpler and less labor intensive process of fender dent repair anddent repair in general.

OBJECTS OF THE PRESENT INVENTION

It is an object of the present invention to have a set of tools forpaintless dent repair having significantly fewer individual toolcomponents than is the current practice

It is another object of the present invention to provide a variety ofhandle shapes orientable in different positions in relative to theworking tip of the tool

It is another object of the present invention to provide a tool set thathas the same, similar, or improved operational feel and performance asare the tool sets of the current practice.

It is another object of the present invention to provide attachmentmeans for attaching non-conventional, special purpose handles to aconventional style dent tool shaft.

It is another object of the present invention to make provisions forattaching extension shafts between the handle and working tool shaft.

It is another object of the present invention to provide handles ofvarious weights or to be able to be weighted with lead or iron slugsinside a tubular outer form.

It is another object of the present invention to provide handles thatcan be adapted to tools other than dent repair tools.

The invention described herein fulfills all these objects and others notenumerated.

SUMMARY OF THE INVENTION

Most of the paintless dent repair tools that are the subjects of thisimprovement in the art of automobile body repair and similarapplications have a long thin rapier like shape with a tip on the distalend adapted for urging or forcing a dent from the back side. On theproximal end of the shaft is a fitting adapted to cooperate with acomplementary fitting on a handle piece, thereby permitting a handle tobe removably attached to the shaft. Said handles are designed formanipulation of the distal end in tight places, and since the handlepiece may be in interference with another portion of the automobilebody, there must be a variety of offsets available in either or both thehandle shape and the attachment to the shaft.

To provide for a stable, yet orientable, attachment of the handle to theshank, the joining means has a square tang that fits into a squaresocket as part of the handle subassembly and accidental disassembly isprevented by a set screw, a pin, or other retention means. The squaretang and socket will connect in any of four radial orientations.

The new handles may emulate the handles found in the art or bespecifically constructed to better fit the craftsman's hand. Variousshapes, in particular a serpentine form and an L form are preferred. Theserpentine or S shaped handle has operating characteristics similar to aT handle.

The new fender dent repair tool is a heavy duty puller which uniquelyhas a second handle near the working tip. The second handle permits theuse of two hands to apply force and to control the placement andstability of the working tip on the dent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is prior art showing a typical tool from a set of availablepaintless dent repairing tools.

FIG. 2 is an overall view of a typical tool from a set of the presentinvention.

FIG. 3 is a cross section detail of the joining means between a handleand shank of a tool from the present invention tool set.

FIG. 4 shows the cooperating elements of the joining means of thepresent invention.

FIG. 5 shows a variety of handles from the present invention tool set.

FIG. 6 shows a 3-section handle with thumb rest.

FIG. 7 is a specialized tool for repairing dents along the edge of awheel fender.

FIG. 8 shows a handle socket detail showing a holding means for an Allenwrench.

FIG. 9 is a forward handle with clamping means.

INDEX OF COMPONENT IDENTIFIERS

-   1. Prior art tool, overall-   2. Tool working tip-   3. Shank-   4. Handle-   5. Offset portion-   6. The present invention, overall-   7. Joining assembly-   8. Handle, typical-   9. ½ of joining assembly-   10. ½ of joining assembly-   11. Tang (a.k.a. pin, post, shaft, rod) element of coupling assembly-   12. Receiving hole for tang of joining assembly-   13. Setscrew-   14. Weld-   15. Detente cooperating with a setscrew-   16. Generals angle between the axis of coupling and the gripping    portion of the handle.-   17. A general offset angle between the axis of the joiner and the    handle-   18. Thumb rest section of handle-   19. Thumb rest button-   20. Allen wrench receiving slot-   21. Allen wrench receiving hole-   22. Fender tool shank-   23. Fender tool shank offset segment-   24. Fender tool hook-   25 Fender tool working tip-   26. Fender tool forward handle-   27. Angle for thumb rest segment-   28 a. Lower clamp plate-   28 b. Upper clamp plate-   29. Shank retention groove-   30. Clamp assembly screws-   31. Handle piece

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 is representative of a typical paintless dent repair tool (1) inthe prior art It is comprised of three essential parts, a working tip 2at the distal end, a long thin shank 3, and a handle 4 at the proximalend. Typically, the handle is a length of the shank stock formed into aloop or L then covered with a vinyl or similar protective coating forproviding both gripping friction and avoiding metal contact with theauto body under repair. As can be seen, the whole assembly is fixed. Thehandle is a light structure and is in a fixed orientation with theworking tip. A set of tools usually contains several tools with thedistal end bent into either a radially projecting segment 5 or a hook. Ahook if used, is often an arc of approximately 180 degrees for workingthe far side of a dent.

A full set of paintless dent repair tools may be as many as 300individual tools. If each has a handle made from 20 inches of highquality steel, approximately 40% of the steel used in the prior art isused in handles. One can see that the present invention results in largesavings of quality material, plastic handle covering, and fabricationsteps.

Dent removal is a pragmatic art and when necessary, tools are fabricatedfor special circumstances. This is a situation usually avoided as it islabor intensive and the most readily available source of materials is atool in the set on hand. Because the present invention has a variety ofinterchangeable components, the occasions where custom fabrication areminimized. Furthermore, since there is less length in the shank portion,common material from around the shop may suffice for one-time use.

The present invention (6) as shown in FIG. 2 utilizes industryrecognizable shanks 2 and tip assemblies, but the shanks are fitted withjoiner part 7 for receiving a handle 8.

FIGS. 3 and 4 illustrate the details of the preferred embodiment of thehandle to shank joining means.

The shank 3 is fastened to a first portion of the joiner 9, and thehandle terminus comprises a structure as a second cooperating portion 10of the joiner assembly (7). One portion of the joining means furthercomprises a tang structure 11, shown in FIGS. 3 and 4 as a square rod,which fits within a matching square hole 12 in the other portion. Toavoid unintentional disengagement, a retention means is employed. Theillustrations show a set screw 13 in the handle and a cooperatingdetente 15 in a square tang. Other retention means are anticipated andmay be freely substituted. Among them, bolts, bolts with knobs or wings,through pins such as cotter pins or roll pins, ball and springassemblies, etc.

The tang must be long enough and have sufficient cross section towithstand bending and torsional forces encountered while using the tool.A steel tang having dimensions of ⅜ inch square with a length of 1 inchhas been found sufficient. Shorter tangs put additional stress on thecoupling socket which unless made a larger diameter, may result in thesquare socket hole being distorted or broken out. Longer tangs reducethe stress and permit use of a smaller diameter joiner body. Small toolsmay use ¼ inch square tangs, although their inclusion increases thenumber of handle pieces in a set. A diameter of ⅝ to ¾ inch has beenfound satisfactory for the joining body which is usually carried intothe handle portion at the same diameter.

The gripping portion of the handle may also be fitted with an elasticgrip such as a piece of tubing, a bicycle handle grip, or similar.

Shank 3 is shown attached to the associated joining member by welding14. “Welding” should be interpreted broadly to include similar processessuch as soldering, brazing, and glueing. Other attachment methods areanticipated, such as casting, forging, swaging, and various interferencepress fits including upsets such as knurling and splines. Alsoanticipated are threaded tangs and chuck-type assemblies. Also includedis having the proximal end of shank 3 squared and secured with asetscrew, or threaded. A squared or threaded shank may be attached toeither a transition joining assembly as described or directly into thehandle socket. Thus, eliminating ½ of the joining means altogether. Allthese methods of joining the handle and shank have the commoncharacteristic of that the shank is firmly and non-rotatably attached tothe handle.

It should be obvious that the two joiner halves can be interchanged,that is, the half with the tang can be on the handle half and the holein the shank half without diminishing the utility, way, mode, orfunction of the handle to shank joining device. Similarly, should beobvious that the tang may be a third and separate component with bothjoiner halves having cooperating holes and retention means.

FIG. 5 shows a representative set of the most common handle shapes.Shown are a serpentine or S shape, an L shape, and a T handle. Notshown, but intended to be included in the mix are ring grips, D grips,grips coaxial with the shank, and grips emulating the prior art. Thejoiner socket detailed in FIG. 6 is applicable to all the variantsillustrated in FIG. 5 and other compatible handle designs.

The angle 16 between the shank axis and the gripping portion may bevaried to suit any anticipated applications. The angle of offset 17 awayfrom the axis of the shank may be any varied to suit any anticipatedapplications. Generally angle 16 will be 90 degrees for T and S handlesand approximately 100 degrees for L handles, but a range of 45 to 135degrees will cover most applications. Generally, the offset angle 17will be 0 degrees, but a range of zero to 90 degrees will besatisfactory for most applications.

FIG. 6 is a preferred variation on the L handle shown in FIG. 5. FIG. 6includes three details not shown in the other figures. First, the squaresocket (or a tang) 12 is located on each end of those handle embodimentswhere it is practical to use either end. This effectively doubles theoptions of usage. The second socket may be offset 45 degrees,effectively providing eight positions of rotation as well as a differentconfiguration of handles. Second, instead of an arc joining the twosegments of the L handle there is a short approximately straight segment18. This portion serves as a thumb rest which is more comfortable than acircular arc as illustrated in FIG. 5. Third, a special thumb rest area19 for receiving the thumb is provided. The general cylindricalcurvature of the handle stock localizes the pressure on the thumb. Thethumb rest spreads out that load. The thumb rest depicted is a dipground or forged into segment 18. A thumb rest may be a separate pieceof plastic or metal attached to the handle.

The handles of the present invention have larger diameter grippingsurfaces than the prior art.

They also may be constructed of heavier material to provide more inertiato use the tool as a hammer to apply taps or blows to very preciseplaces on the backside of the dent being repaired. The handles may befilled with heavy material such as lead or even temporary weighting suchas lead shot or slugs, or sand, and the like to provide weight asneeded.

In the case of the T, S, D, and some other handle shapes, a portion ofthe handle is in line with the axis of the shank thus pushing, tapping,or jigging on the handle sends force down the shaft to the tip. This isnot possible with the prior art tool depicted in FIG. 1.

Another very positive attribute of the present invention over the priorart is that the removable shank portion is essentially straight, thus,they may be stored compactly in an elongated tool box, a golf club bag,or similar.

Experience with the new tool bears out the design goal that because thehandle can be rotated relative to the working tip, it is morecomfortable, easier to apply and control the working forces, and is notrestricted by interference with the automobile body being repaired. Partof the success of the invention is credited to the larger diameter andrigidity of the handle element. In contrast, the prior art tool handleportion is thin and flexible. The thinness of the prior art handleproduces much higher pressures on the palm of the hand for the sameworking forces at the tool tip. The flexibility of the prior artinterferes with the “feel” of sensing pressures, especially in twistingactions.

FIG. 8 details an embodiment of the socket end further comprising aholder for the Allen wrench used to tighten setscrew 13. A hole 21receives the long end of a standard Allen wrench, and slot 20 permitsthe short end to be below the end surface of the square socket 12. Tokeep the Allen wrench from dropping out, a piece of resilient materialmay be inserted in hole 21 or another small piece of resilient materialsuch as a nylon screw may be inserted through a hole drilled radiallyfrom the handle surface into hole 21.

Alternatively, the Allen wrench may be bent slightly and will grip thesides of the receiving hole 21.

FIG. 7 depicts a new specialized tool for repairing dents in the edgesof a fender. A typical fender has a rolled bead or inwardly directedstiffening rib on the edge near the tire to add strength and form asmooth, rounded edge. These add significant stiffening to the fender andsubsequent dent repair will require much larger forces and more finessein the application of those forces than is usual for mid-panel dentrepair.

The tool shown in FIG. 7 is made of heavier stock and has a uniqueforward handle 26 for two-handed application of increased force andbetter control of the working tip. In addition, the handle can act as afulcrum point by placing a block of wood or similar between the handleand the tire, thereby permitting the repair forces to be applied throughleverage actions.

Referring to FIG. 7, handle 8 is one of the embodiments previouslydescribed. Shank 22 is a rod approximately 12 to 20 inches long and ofsufficient strength to support the necessary loads of the repairoperation. Offset 23 is optional. Hook 24 is approximately 4 inches indiameter, but may be more or less. Its purpose is to align tip 25 toenable the tip to transfer force perpendicular to the dent. The diameterof the hook is not critical, and smaller diameters are for working moreclosely to the fender edge. Larger diameters can reach further into thewheel well. The hook can also reach and grab any internal bracing thatmay have been crumpled. Most of the paintless dent removal tools areused within auto body cavities and there is no room for forward handles.However, the fender area is open and a forward handle 26 is ofconsiderable assistance to the dent repair artisan. Furthermore, someother dents are near enough to an edge or entrance or are on more openpanels such as engine compartment hoods, trunk lids, and roofs. Forrepairing dents like these, a removable, adjustable forward handle mayprove useful in controlling the forces and in the placing of the workingtip. Also, with a forward handle, a tool that is longer than optimum maybe used, thereby reducing the number of various shank lengths needed ina repair tool set. A forward handle may be either fixedly attached tothe shank, or it may be clamped to the shank.

Clamping permits variable axial and radial placement of the handle.

FIG. 9 shows a typical forward handle comprising handle piece and clampassembly. The clamp comprising fixed 28 a and movable parts 28 b with ashank retention groove 29 is attached to a handle piece 31. Screws 30provide the closing and clamping forces. The clamp can be applied to anyportion of the shank and turned to any radial angle before tighteningthe screws.

How to Use the Invention

Paintless dent repair is an art requiring much practice to applyefficiently, therefore, much of how to use the tools cannot bedescribed, but in general, for the current invention, the shank with themost appropriate shape is selected, a handle is selected and attached tothe shank in a position where it will be both comfortable to use and notbump into the automobile under repair. The dent is removed by applyingpressure at an artfully selected series of spots on the back of the dentby pushing, pulling, twisting, or some combination of those efforts onthe tool.

Alternate Embodiments

The figures show the tang being square being a square rod. Obviously,other shapes will provide the same or enhanced functional ability. Inparticular, hexagonal and octagonal shapes are easy to manufacture andoffer a larger number of optional rotational positions than a squarerod. Another embodiment of the tang is to replace the polygonal shapedrod with a round rod (ie. pin or cylinder) having an annular ring cutaround the surface for engaging the setscrew point. Alternatively, inplace of an annular ring, a series of detentes in the same track wouldprovide better resistance against rotation. Another embodiment is toreplace the tang with a threaded rod. Flat and wavy (spring) washers ora thin lock nut between the two halves of the joiner would be used toadjust rotational position of the handle relative to the shank's workingtip.

The various embodiments of the tang described may be implemented as aseparate threaded or polygonal rod sliding into matching holes in bothof the joiner elements attached to the handle and shank. It is alsoobvious that such a pin element may have differently shaped ends as longas the whole joining assembly rigidly connects the handle to the shank.

Another embodiment for the tang structure is to swage, forge, or grindthe proximal end of the shank into the tang shape, thereby eliminatingthe extra pieces and steps pertaining to the shank end joiner mechanismwithout diminishing the operation and function of the tool with theimproved handle.

Another embodiment for the tang function is to have a plurality of pinsor rods and cooperating holes arrayed evenly spaced around a circularlocus. Only one pin and hole pair needs to have a retention means. Oneor more pins may protrude through part of the joint assembly and bethreaded and secured with a nut or equivalent.

An extender comprising a shaft with each half of the described connectorassembly on each end may be part of the tool set. The extender would beinstalled between the handle and the tool shank.

The ball handle shown in FIG. 5 may have alternate shape such as ovoid,“foot ball” shape, or simply large diameter cylinders. The disk handleshown also includes various non-circular shapes and shapes comprisinggrip enhancing fluting or projections.

Although the present invention has been described in considerable detailand with reference to certain preferred versions, other versions arepossible. For example, while a considerable number of componentdimensions have been given, they are illustrative only of the preferredembodiment, and some alterations could be resorted to, while still inkeeping within the teachings of the invention. Therefore, the spirit andscope of the appended claims should not be limited to the description ofthe preferred and alternative versions disclosed.

The invention has been described in language more or less specific as tomethodical features. The invention is not, however, limited to thespecific features described, since the means herein disclosed comprisethe preferred forms of putting the invention into effect. The inventionis, therefore, claimed in any of its forms or modifications within theproper scope of the appended claims appropriately interpreted inaccordance with the doctrine of equivalents.

1. An automobile body dent repair tool comprising in combination: a. an elongated shank having distal and proximal ends, and b. at least one handle, and c. a joining means for releasably attaching a handle to said proximal end of said shank, and d. said joining means further comprising at least one rod and a like number of holes adapted to receive said rods, and e. said joining means further comprising a securing means for preventing disengagement, and f. when joined, said shank and handle are rigidly joined and comprise a tool having a handle at proximal end and a working tip at the distal end.
 2. The dent repair tool of claim one where said joining means having first and second parts, the first part having an axially extending tang having a polygonal cross section and the second part having an axial hole adapted to receive said polygonal tang in a sliding engagement, said first part attached to said shank, and said second part attached to said handle, whereby when said two parts are joined, said handle and said shank are securely connected.
 3. The dent repair tool of claim 1 where said joining means having first and second parts, the first part having an axially extending threaded tang, and the second part having a threaded axial hole adapted to receive said tang in a threaded engagement, whereby when said two parts are joined, said handle and said shank are securely connected.
 4. The joining means of the dent repair tool of claim 1 further comprising a rod and where said joining means having first and second parts each having an axially located hole adapted to receive said rod, whereby said rod engaging said holes joins said handle and shank in a securely connected alignment.
 5. The dent repair tool of claim 1 further comprising a plurality of interchangeable handles and a plurality of interchangeable shanks, and each handle and shank having cooperating joining means to removably attach said handles to said shanks in a securely connected alignment, thereby comprising a dent repair tool.
 6. The dent repair tool of claim 1 further comprising a second handle attached near the distal end of the shank.
 7. The second handle of the dent repair tool of claim 6 is fixedly attached to the shank.
 8. The second handle of the dent repair tool of claim 6 is removably attached to the shank.
 9. The dent removal tool of claim 1 further comprising an extension means comprising a shaft having joining means adapted to couple with cooperating portions of said joining means of claim 1, whereby said extension means is in a securely connected alignment between said handle and said shank, thereby forming an extended dent repair tool
 10. The handle at the proximal end of said shank of the dent repair tool of claim 1 further having a thumb rest.
 11. An automobile body dent repair tool comprising in combination: a. an elongated shank having distal and proximal ends, and b. at least one handle, and c. a joining means for releasably attaching a handle to said proximal end of said shank, and d. said joining means further comprising a rod and cooperating hole adapted to receive said rod, and e. said cooperating rod and hole further comprising anti-rotation means to prevent axial rotation between said rod and hole, and f. said joining means further comprising a securing means for preventing disengagement, and g. when attached, said shank and handle are rigidly joined and comprise a tool having a handle at proximal end and a working tip at the distal end.
 12. The dent repair tool of claim 11 further comprising: said rod and hole having a polygonal cross sectional shape.
 13. The dent repair tool of claim 11 further comprising: said rod and hole having threaded engagement means. 